Communications technologies and uses have greatly changed over the last few decades. In the fairly recent past, copper wire technologies were the primary mechanism used for transmitting voice communications over long distances. As computers were introduced the exchange of data between remote sites became desirable for many business, individual and educational purposes. The introduction of cable television provided additional options for increasing communications and data delivery from businesses to the public. As technology continued to move forward, digital subscriber line (DSL) transmission equipment was introduced which allowed for faster data transmissions over the existing copper phone wire infrastructure. Additionally, two way exchanges of information over the cable infrastructure became available to businesses and the public. These advances have promoted growth in service options available for use, which in turn increases the need to continue to improve the available bandwidth for delivering these services, particularly as the quality of video and overall amount of content available for delivery increases.
One promising technology that has been introduced is the use of optical fibers for telecommunication purposes. Optical fiber network standards, such as synchronous optical networks (SONET) and the synchronous digital hierarchy (SDH) over optical transport (OTN), have been in existence since the 1980s and allow for the possibility to use the high capacity and low attenuation of optical fibers for long haul transport of aggregated network traffic. These standards have been improved upon and today, using OC-768/STM-256 (versions of the SONET and SDH standards respectively), a line rate of 40 gigabits/second is achievable using dense wave division multiplexing (DWDM) on standard optical fibers.
In the access domain, information regarding optical networking can be found in Ethernet in the First Mile (EFM) standards (IEEE 802.3ah which can be found at www.ieee802.org and is included herein by reference) supporting data transport over point-to-point (p2p) and point-to-multipoint (p2mp) optical fiber based access network structures. Additionally the International Telecommunications Union (ITU) has standards for p2mp relating to the use of optical access networking. Networks of particular interest for this specification are passive optical networks (PONs). For example, three PONs of interest are, e.g., Ethernet PONs (EPONs), broadband PONs (BPONs) and gigabit capable PONs (GPONs), various exemplary characteristics of which are displayed below for comparison in Table 1.
TABLE 1Major PON Technologies and PropertiesCharacteristicsEPONBPONGPONStandardIEEE 802.3ahITU-T G.983ITU-T G.984ProtocolEthernetATMEthernetRates (Mbps)1244 up/1244 down622/1244 down1244/2488 down155/622 up155 to 2488 upSpan (Km)102020Number of163264Splits
With these ongoing improvements in optical networks, many telecommunication companies are choosing to upgrade their copper centric access networks with fiber optic access networks. Some such upgrades include, for example, using one of the above described PON networks combined with fiber to the home (FTTH), and/or hybrid networks, e.g., fiber to the cabinet (FTTC) combining optical EFM and/or PON for data backhaul with very high speed digital subscriber line (VDSL2) by reusing the last hundred meters or so of copper wire. These upgrades allow an increase in the types and quality of services delivered by companies to end users. As such services are deployed, there will be more demand for these networks and it will be desirable to be able to deploy PONs (and other networks) which are, for example, both flexible, e.g., from a manufacturing and supplier perspective, and scalable to meet this demand.
Like many other communication systems, lower level protocols are provided in PONs which are responsible for packaging and routing higher level data. Such lower level protocols generate data frames or packets which can generally be characterized as having a control (overhead) portion and a user (data) portion, although each of these portions may be further subdivided into a number of different fields. Although each frame or packet will typically include both a control portion and a user portion, these two portions may have different time criticality relative to the consumer (recipient) of the frame or packet. Additionally, the control portion may, itself, have some fields whose values are repeated in some or all of a number of sequentially transmitted frames, while other fields have values which change more rapidly, e.g., from frame to frame. Also, the time criticality of receipt by the downstream consumer of the frame for each field within the control portion may vary from field to field.
Accordingly, it would be desirable to provide methods and systems which provide flexibility to the manner in which data frames or packets are constructed.